Molecular cloning of a functional cis-acting, Bam HI-flanked, 1.6 Kb 'Mob' cassette for demonstrating rapid conversion of col EI origin-DNA cloning vectors into conjugal form.

A 1.6 Kb mobilization (Mob) fragment originating from broad host range IncP plasmid RP4 is effectively cloned into two different Col EI-origin based cloning vectors, pBluescript II SK+ and pT-Adv, to generate pPAR-I and pPAR-II, respectively. The vectors have different genetic markers and were demonstrated to get mobilized at significant frequency into a laboratory and an enteroroxigenic strain of Escherichia coli with all the genetic markers of the recombinant clones expressing efficiently in the recipient host cells. Important restriction endonuclease recognition sequences in the multiple cloning sites of the conjugal vector DNA molecules remained unique. Significance and relevance of the current study with regard to other gene delivery system in gram negative bacteria are discussed.